Matrix
Added in version 1.6.
- class Matrix(*args, **kwargs)
- Constructors:
Matrix()
Methods
- class Matrix
- concat(new_matrix: Matrix) None
Changes the transformation represented by
matrix
to be the transformation given by first applying transformation given bynew_matrix
then applying the original transformation.Added in version 1.6.
- Parameters:
new_matrix – a
PangoMatrix
- get_font_scale_factor() float
Returns the scale factor of a matrix on the height of the font.
That is, the scale factor in the direction perpendicular to the vector that the X coordinate is mapped to. If the scale in the X coordinate is needed as well, use
get_font_scale_factors
.Added in version 1.12.
- get_font_scale_factors() tuple[float, float]
Calculates the scale factor of a matrix on the width and height of the font.
That is,
xscale
is the scale factor in the direction of the X coordinate, andyscale
is the scale factor in the direction perpendicular to the vector that the X coordinate is mapped to.Note that output numbers will always be non-negative.
Added in version 1.38.
- get_slant_ratio() float
Gets the slant ratio of a matrix.
For a simple shear matrix in the form:
1 λ 0 1
this is simply λ.
Added in version 1.50.
- rotate(degrees: float) None
Changes the transformation represented by
matrix
to be the transformation given by first rotating bydegrees
degrees counter-clockwise then applying the original transformation.Added in version 1.6.
- Parameters:
degrees – degrees to rotate counter-clockwise
- scale(scale_x: float, scale_y: float) None
Changes the transformation represented by
matrix
to be the transformation given by first scaling bysx
in the X direction andsy
in the Y direction then applying the original transformation.Added in version 1.6.
- Parameters:
scale_x – amount to scale by in X direction
scale_y – amount to scale by in Y direction
- transform_distance() tuple[float, float]
Transforms the distance vector (
dx
,``dy``) bymatrix
.This is similar to
transform_point
, except that the translation components of the transformation are ignored. The calculation of the returned vector is as follows:dx2 = dx1 * xx + dy1 * xy; dy2 = dx1 * yx + dy1 * yy;
Affine transformations are position invariant, so the same vector always transforms to the same vector. If (
x1
,``y1``) transforms to (x2
,``y2``) then (x1``+``dx1
,``y1``+``dy1``) will transform to (x1``+``dx2
,``y1``+``dy2``) for all values ofx1
andx2
.Added in version 1.16.
- transform_pixel_rectangle() Rectangle
First transforms the
rect
usingmatrix
, then calculates the bounding box of the transformed rectangle.This function is useful for example when you want to draw a rotated
PangoLayout
to an image buffer, and want to know how large the image should be and how much you should shift the layout when rendering.For better accuracy, you should use
transform_rectangle
on original rectangle in Pango units and convert to pixels afterward usingextents_to_pixels
’s first argument.Added in version 1.16.
- transform_point() tuple[float, float]
Transforms the point (
x
,y
) bymatrix
.Added in version 1.16.
- transform_rectangle() Rectangle
First transforms
rect
usingmatrix
, then calculates the bounding box of the transformed rectangle.This function is useful for example when you want to draw a rotated
PangoLayout
to an image buffer, and want to know how large the image should be and how much you should shift the layout when rendering.If you have a rectangle in device units (pixels), use
transform_pixel_rectangle
.If you have the rectangle in Pango units and want to convert to transformed pixel bounding box, it is more accurate to transform it first (using this function) and pass the result to
extents_to_pixels()
, first argument, for an inclusive rounded rectangle. However, there are valid reasons that you may want to convert to pixels first and then transform, for example when the transformed coordinates may overflow in Pango units (large matrix translation for example).Added in version 1.16.
- translate(tx: float, ty: float) None
Changes the transformation represented by
matrix
to be the transformation given by first translating by (tx
,ty
) then applying the original transformation.Added in version 1.6.
- Parameters:
tx – amount to translate in the X direction
ty – amount to translate in the Y direction